Path to collapse for an isolated N\'eel skyrmion

TL;DR

This paper uses a path method with atomic scale simulations to analyze skyrmion collapse mechanisms in a Co/Pt(111) monolayer, revealing two distinct paths and emphasizing the role of Dzyaloshinskii-Moriya interaction in stability.

Contribution

It introduces a general path method for skyrmion collapse analysis and identifies the dominant role of Dzyaloshinskii-Moriya interaction over topology in stability.

Findings

Two collapse mechanisms with different energy barriers identified.

Lowest energy barrier path aligns with Langevin dynamics results.

Topology plays a minor role in skyrmion destabilization.

Abstract

A path method is implemented in order to precisely and generally describe the collapse of isolated skyrmions in a Co/Pt(111) monolayer, on the basis of atomic scale simulations. Two collapse mechanisms with different energy barriers are found. The most obvious path, featuring a homogeneous shrinking gives the largest energy, whereas the lowest energy barrier is shown to comply with the outcome of Langevin dynamics under a destabilizing field of 0.25 T, with a lifetime of 20~ns at around 80~K. For this lowest energy barrier path, skyrmion destabilization occurs much before any topology change, suggesting that topology plays a minor role in the skyrmion stability. On the contrary, an important role appears devoted to the Dzyaloshinskii-Moriya interaction, establishing a route towards improved skyrmion stability.